The article kind of explains why he did it - Pulp used to play the Adelphi a lot in the mid '80s, it was one of the first places outside of Sheffield where they played to a decent audience, so it must hold fond memories for him.
The 180 must be the capacity of the venue. And presumably it was invite only because it was a special event that they didn't want any old Tom Dick and Harry coming along to.
__________________
"Yes I saw her in the chip shop / so I said get yer top off"
Nice clips of the gig from youtube(Strange, as I remember looking for videos of the night a couple of months ago and couldn't find anything):
He mentions the Adelphi being part of Pulp's heritage at the end.
Also, here's a bbc report on the gig:
Nice comment from a member of the audience at the beginning of the gig: ''Where's your wheelchair?!'' Presumably, a veteran of mid-80s Pulp concerts as opposed to a heckler telling Jarvis that he's past it (though a lot of the audience, not au-fait with Jarvis' experience with wheelchairs, may have thought that is what he was on about).
